Hand Crank Flashlight

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FAQ about Hand Crank Flashlight

Where can I buy a Mini Hand Crank Flashlight? ive looked everywhere D: like xs cargo, canadian tire, source ... i cant find it D: Try Here:
http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2Fgp%2Fhomepage.html&tag=tubeblog-20&linkCode=ur2&camp=1789&creative=9325
Or try searching ebay
http://rover.ebay.com/rover/1/711-53200-19255-0/1?type=1&campid=5336006644&toolid=10001&customid=
Good Luck

How do i find the induced current made from a hand crank flashlight? I'm starting on a project for my physics class, and I need to do analysis on a hand crank flashlight, and I'm having a hard time getting started on finding the induced current and the magnetic field. To measure the induced current, just put an ammeter in series with the bulb.
The magnetic field depends on the number of turns of the armature and the speed of rotation.  I'm not sure why you'd be asked to calculate that unless you are given other data.

How does a hand crank flashlight work? the crank drives a spring or gear that revolves a magnet around a stationary magnet. the magnet spinning around the stationary one generates electricity through the magnetic fields ripping away electrons from each other. the electricity then travels through the wire to the bulb and you have light.

Are hand-crank flashlights/radios forbidden to be shipped USPS to soldiers? I wish to ship one and would like to know. Nope, they are not prohibited. BUT, make sure you don't put things in the box that are, else nothing will get where it needs to go. Also remember that at some point, the USPS gives teh mail over to the military and it gets it teh rest of the way, so some things also travel with higher prioirity things, like ammo!
Thank you caring about our servicemen and women.

Does anyone own a hand crank flashlight or flashlight you shake to generate power? Do these work well? Would like to buy a flashlight that doesn't use any batteries. I had problems of leaky batteries after I left my flashlight in the trunk of my car for a couple of years. I've seen these types of products all over the internet for camping and emergencies. Do these work well? Hand crank ones could be more efficient as the cranking motion could generate more energy. Search Amazon and they run about $10 + s/h. Some even have cell phone charging, albeit for mostly Nokia phones.

Extremely bright hand cranked flashlight for survival? Anyone know of a good one? Bright, very durable, nearly military grade. Or an alternative you guys can think of? The military doesn't much care for crank flashlights. They make noise. They also don't want to give away their position with a flashlight. Most of the crank lights require you to crank them repeatedly since they start dimming down very quickly. I've yet to find one that keeps a charge for more than three or four minutes.

if i hook up a generator dc motor (maybe from a hand crank flashlight and then hook it up to some rechargble? rechargble batteries will it charge the batteries? Yes it will work.
You need to put a blocking diode between the motor and the battery so the battery doesn't just start running the motor! If your charging just one NiCD or NiMH cell (1.2V) it should work pretty good. Any higher voltage and you will really have to get the rpms up on the motor with gearing etc. to produce enough voltage.
Don't try to charge bare lithium batteries though. They have a nasty habit of exploding in spectacular fashion they are over charged (don't ask how I know). They also have failure modes when they are over discharged.

Anyone know of a hand-crank/dynamo flashlight that can also charge an iPhone? I have survived a few hurricanes without power, it can get get annoying winding things. Go for solar power for your phone with maybe wind up for a backup. There are also solar powered florescent lights that you can read by, keep the two separate in your priorities. What are planning on doing that you will need alternate power?

hand crank flashlight to bike generator? can i take apart one of those hand crank LED flashlights and take out the part that is being cranked to produce the light. and some how put it on my bike wheel and when i pedal the bike it spins and recharges a 12v marine battery? any suggestions??? thanks im not using the battery to power the bike. im using the battery for my boat Max output capacity of those generators is only a few dozen milliamps, if that - if your battery is about the same size as a typical car battery, then it's capacity would be about 100 amp-hours. Therefore it would take dozens to hundreds of hours to recharge it.
An automotive alternator and regulator is much more appropriate. About the right gear ratio for the alternator pully might be the diameter of a 10-speed's rear tire to the diameter of the alternator's pulley, so a belt large enough to fit both plus an idler pulley to keep it tight on the alternator pulley might get you there, and the gears of the bike can fine-tune it to your physical capacity. One way to calculate how much you'll have to pedal -
1) Assume your leg's max pedal output for an extended time to be say 1/5 horsepower if you're in pretty good shape, maybe 1/3 if you're Lance Armstrong
2) Assume bike/alternator/regulator/battery chemistry net efficiency to be about 50% (sorry, that's about the best considering total losses)
3) Assume battery depletion to be 75%, leaving it only 25% charged (this is as far as you should go even with a deep-cycle marine battery)
4) Then minimum required energy in watts into the battery would be the amp-hour rating of the battery times the 75% percent figure times 3600 (seconds per hour) times charging voltage of 13.5V divided by the efficiency losses of 50%
Ex - 100 amp-hour battery * 75% * 3600 / 0.5 = 540000 watt-seconds, aka joules
Divide that by the constant 745 to get horsepower-seconds, which would be 725. If you're going to kick at 1/5hp, then the time you'll need to pedal your azz off would be
725/(1/5) = 725 * 5 = 3625 seconds, or slightly more than 1 hour.
...I think I got that all right....
...or, you could just jumper the battery to your car's battery while the engine is idling for about 20 minutes....

How does a hand cranked flashlight work? Does anyone know the science behind a hand-cranked flashlight? Only if you definately know you are correct. Thanks! There are two types.
Most with a folding handle have a small generator attached which drives a current through a rechargeable battery. The battery in turn supplies power to the light ( these days an bank of LEDs )
Some "shake" flashlights work by sliding a magnet up and down through the wire coils. This is just a rearrangement of a simple generator but the current in this case is directed to a capacitor which does the energy storage.
You want the energy ocnversion chain?
Muscles convert stored chemical energy into rotational kinetic energy. The generator converts the KE into electric energy. The battery converts electric energy into chemical potential energy. The LED, by allowing a current, enables the battery to convert its chemical energy back into electric energy which the LED converts to light energy ( and a bit of heat.)

Hand Crank Flashlight is from category: Flashlights.